Unlike some modern cars with their "flimsy" engine parts (to save weight), these older cast iron motors and cyl heads can take heat and live to tell about it.
At one itme, the radiator in my '80 Newport 360 2bbl had a few pinholes in the upper tank. It was at my shadetree shop, which is a good 30 minutes on the freeeway from home. I was going to "nurse" it home one afternoon. I knew where the "water stops" would be around the loop, so I headed out with tnose in mind. By the time I got to the first one, the gauge was already near the top, so I stopped to run some water on the radiator, then carefully removed the radiator cap to add a bit of water. Ready fo rthe next stop, about 10 minutes away. Same thing. Then for the longest leg of the trip.
I was not driving it hard and was not running the speed limit. Near the end of this leg, I pondered if I should be on the access road. That 360 was sounding like the overheated Valiant in the Dennis Weaver movie where a mysterious, driverless tanker truck was chasing him through the desert. It was clattering at the slightest hill or acceleration, but we made it to the next stop. By this time, it was night. It must have taken over an hour for the heat gauge needle to return from its hiding place behind the rh side of the gauge (when it got that far, the LED indicator lamp was out, too!). Eventually, I got the engine cool (a relative term at this point) enough to take little bits of watter through the radiator's top tank. I certainly did NOT want to put cool rater inth the engine! But eventually, I was able to put water into the radiator and it stay there. The temp gauge needle came out of hiding and all was still well. I eased it back to the house (about 15 minutes away). I moved a car from out from under the carport as I knew that where the car stopped, it would stay there for several days. When I finally turned off the engine, it was as if nothing had happened! I had raised the hood to make one last inspection before I turned it off. Leaving the hood up so the engine could convection cool overnight.
A few days later, I pulled the dipstick out to check the oil. The Castrol GTX 10W40 just looked normal. NO water in it at all. Then I later took a used radiator out of a '79 Gran Fury 360 4bbl sherriff's car to the radiator shop to get it ready to install in the '80 Newport. I also got a pair of Mr. Gasket valve cover gaskets, as I wanted to take the valve covers off to look for any signs of failure in the heads. THAT is when I saw evidence of "heat". The vc gaskets on the motor were "crispy crittered", as in "crispy". Still, no signs or smells of "heat" for extended periods of time outside fo the valve cover gaskets. So I gave the gaskets a coat of black, high-heat sealer, letting it cure overnight, and put things back together.
When I did an oil/filter change, the oil draining out acted "normal", too. No evidence of water, either! Still a bit skeptical, I did the oil change, put the re-done radiator in, put pure water in the engine for testing (as I had been told, ages ago, that water would not leak out but an anti-freeze mixture WOULD. I used the water for testing, starting with short trips in town, increasing the length and run time, progressively. After several weeks, I got enough confidence to go on a 200 mile drive. Everything worked well. So I drained out the water, which was sitll clear, and added coolant into the mix. More checks and looks and such. Everything was normal. So I began driving the car more and more until it was "daily". No evidence of combustion gasses in the coolant and no moisture in the motor oil.
When I was in college, one of my profs had a Jensen Healy as his daily driver and auto-cross car. The earlier ones were known to have water pumps which could fail unexpectedly. He told me about a time that happened about half way between Amarillo and Lubbock. He found one of those little gas stations on the edge of a cotton field and used that to get the car cooled down and continued to Lubbock and got a new pump installed. His testimony was the reason I started to use an oil "that fights viscosity breakdown", before that was in their advertising to the extent it later was. He said when he sold the car, he instructed the new owner to only use that brand and viscosity of motor oil. A month or so later, he got an angry call from the new owner about selling him a defective car. Seems the new owner took the car to a local dealer to get the oil changed. They used a brand of motor oil seemingly preferred by drag racers. The water pump had failed in afternoon traffic and the motor cooked. My prof asked if he specified the use of the brand of motor oil HE had used. No he did not. An attorney later called and my prof recounted what he had told the buyer. The buyer confirmed that. End of story.
I have pondered how that 360 survived what it did, but I know it did survive nicely. It sat there and happily idled as I tried to get it cooled down, just like everything was normal. Now, I suspected that if that motor ever was taken apart, there might be thin cracks between the valves in the combustion chamber, which would be a reason to put some aluminum heads on it, but everything is still bolted together, years later. No need to take things apart. It would not surprise me if, when all of the bolt torques are removed, the block might crumble, LOL.
I have NO doubt the brand of motor oil saved that motor's rotating assy! The fact that the motor was that hot for that long period of time, and then did not smell like it was cooked, validated their advertising claims, to me. But it was the design integrity of the LA block that was important, too.
So, we might get excited with the temp gauge needle getting just past of the centerline, but "ain't going to hurt anything" on these old Chrysler cast iron motors! No matter the number of cylinders. Quality green coolant and OEM-spec motor oils (SL-rated for the flat tappet motors!), all changed and in good condition, always help, too.
Just MY experiences,
CBODY67
